Probably the most interesting part of the previously discussed 174-page World Bank report on the future of world currencies, is, ironically, the part that deals with the past. In its discussion of why "Historically, one national currency has played a global role—or at most, a few national currencies", the WB analyzes the history of the "reserve" or dominant currency from ancient times, through today. It is an engrossing narrative which ebbs and flows with the rise and flow of the dominant superpower (no surprise there). The bottom line of course is whether or not the US will retain its superpower status in an increasingly multipolar (and developing-led) world. And whether it will be replaced by China...or nobody. The implications for the next reserve currency of choice are substantial.
Historically, one national currency has played a global role—or at most, a few national currencies
Historical records indicate that the silver drachma, issued by ancient Athens in the fifth century B.C.E. was likely the first currency that circulated widely outside its issuing state’s borders, followed by the gold aureus and silver denarius coins issued by Rome, even though the Athenian and Roman currencies circulated simultaneously for some time (see figure B3.1.1). The dominance of the Roman-issued coins was brought to an end as the long cycle of inflation that characterized the economy of the Roman Empire from the first century C.E. through the early fourth century led to a continuous devaluation of the Roman-issued currency, causing it to become increasingly less accepted outside the Roman Empire. Ultimately, the aureus became valued according to its weight rather than its imputed “face value,” trading more as a commodity than a currency outside the Roman Empire and making way for the Byzantine Empire’s heavy gold solidus coin to become the dominant currency in international trade in the sixth century.

By the seventh century, the Arabian dinar had partially replaced the solidus in this role, although the solidus continued to circulate internationally at a debased value (reflecting the high financing needs of the Byzantine Empire) into the 11th century. Large fi scal costs also led to a gradual devaluation of the Arabian dinar starting at the end of the 10th century.

By the 13th century, the fiorino, issued by Florence, was widely used in the Mediterranean region for commercial transactions, only to be supplanted by the ducato of Venice in the 15th century. In the 17th and 18th centuries, the dominant international currency was issued by the Netherlands, reflecting that country’s role as a leading financial and commercial power at the time. At that point, paper bills began replacing coins as the international currency of circulation, even though they were not backed by the Dutch government or any other entity under sole sovereign control.

It was only when national central banks and treasuries began holding gold as reserves, beginning in the 19th century, that bills and interest-bearing deposit claims that could be substituted for gold also began to be held as reserves. This development coincided with the rise of Great Britain as the leading exporter of manufactured goods and services and the largest importer of food and industrial raw materials. Between the early 1860s and the outbreak of World War I in 1914, some 60 percent of the world’s trade was invoiced in British  pounds sterling.

As U.K. banks expanded their overseas business, propelled by innovations in communications technology such as the telegraph, the British Pound was increasingly used as a currency of denomination for commercial transactions between non-U.K. residents—that is, the pound sterling became a more international currency. This role for the pound was further enhanced by London’s emergence as the world’s leading shipper and insurer of traded goods and as a center for organized commodities markets, as well as by the growing amount of British foreign investment, of which a large share was in the form of long-term securities denominated in pounds sterling.

At the beginning of the 20th century, however, the composition of foreign exchange holdings by the world’s monetary authorities began to shift, as sterling’s share declined and the shares of the French franc and the German mark increased. The beginning of World War I in 1914 is widely viewed as signaling the end of Great Britain’s leading role in the international economy and the breakdown of economic interdependence.

Despite attempts to revive the gold exchange standard after World War I and to restore an international monetary order based on fixed exchange rates, the restored system lasted only a few years. The U.S. dollar’s use internationally as a unit of account and means of payment increased during the interwar period, particularly during the 1920s, reflecting the growing role of the U.S. economy in  international trade and finance. Although gold was officially the reserve asset (and the anchor) of the international monetary system following World War II, under the Bretton Woods system of fixed exchange rates, the dollar took on the mantle of dominant international reserve currency. By the early 1970s, however, following the breakdown of the system because of its inherent Triffin dilemma, the major economies moved to implement floating exchange rates.

During the 1980s, the global economy showed indications that it was moving to a multicurrency system in which the Deutsche mark was taking on an expanded role as a key currency, both in Europe and globally. This was due to a combination of factors—low and stable German inflation; credible government policies; deep, broad, and open financial markets; and a relatively high share of differentiated  manufactured exports in Germany’s trade. The introduction of the euro in 1999 and its adoption by a growing number of EU countries in the intervening years has only revived the debate about the dollar’s future role as the dominant international currency.